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Genetic and chemoecological studies on sympatric host shift and host race formation in monophagous sawflies

单食性锯蝇同域宿主转移和宿主种族形成的遗传和化学生态学研究

基本信息

批准号：
02454052
负责人：
NAITO Tikahiko
金额：
$ 3.9万
依托单位：
Kobe University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1992
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-02454052/
关键词：
Host race Host shift Host specificity Oviposition stimulant Gene flow Reproductive isolation Sex pheromone Asymmetrical mating

项目摘要

Mechanisms of the sympatric host shift and host race formation in the field populations of Hemitaxonus japonicus complex were investigated. Main results are as follows:1. The new host race, polyblepharum race is being formed from the original one, tripteron race, in the area of about 10 km wide around 34ﾟ N in the south-western part of Japan without geographical isolation. 2. The adult host selection of two races may be controlled by a polymorphic gene. Their oviposition stimulants are similar but distinct chemical substants, like palmitic acid methyl. 3. Two host races show the very small diferentiation in allozyme polymorphisms and highly repeated DNA sequences. This suggests that the rate of sympatric host race formation is very fast in this sawfly. 4. Some isolating factors such as assortative mating on host plants, asymmetrical mating, larval mortality due to conditioning play important roles for sympatric host race formation. The asymmetrical mating prevents the gene flow from the original host race population to the new one, where the sex pheromones are concerned but not identified yet. 5. We tried to make a new host race in the laboratory. The tripteron race females were crossed to the polyblepharum race males, and the F1 females were mated again with the polyblepharum race males. We have succeeded to get F2 females ovipositing only on Polysticum polyblepharum.

研究了日本半轴蝽田间种群同域寄主迁移和寄主小种形成的机制。主要研究结果如下：新的宿主种polyblepharum race是在原宿主种雷公藤的基础上形成的，它位于日本西南部34个邻近地区，宽约10公里，没有地理隔离。2. 两个小种的成虫寄主选择可能受一个多态基因的控制。它们的产卵刺激物是类似但不同的化学物质，如棕榈酸甲基。3. 两个寄主种族在同工酶多态性和高度重复的DNA序列上表现出很小的差异。这表明该锯蝇同域寄主的形成速度非常快。4. 同域寄主的分类交配、不对称交配、条件作用导致的幼虫死亡等隔离因素对同域寄主的形成起着重要的作用。不对称的交配阻止了基因从原来的寄主种群流向新的寄主种群，其中涉及到性信息素，但尚未确定。5. 我们试图在实验室里制造一种新的宿主种族。将雷公藤种雌性与多睑草种雄性杂交，F1雌性与多睑草种雄性再次交配。我们成功地获得了2只雌蜂仅在多泡草上产卵。